Linux软raid创建

时间：2023-12-22 18:04:14

RAID:

HBA：基于主机的适配器

RAID：Redundent Array of Inexpensive Disks 廉价磁盘阵列

Independent       独立磁盘阵列

Level：仅用于标识磁盘组合方式的不同，不能取代数据备份

raid0，raid1，raid5，raid10，raid50，jbod

raid0：提高读写性能，没有容错能力。至少需要两块磁盘 100%

raid1：至少需要两块硬盘，镜像，硬件容错能力，读性能提升，写性能下降 50%

raid4：至少需要三块硬盘，允许一块盘出错，读写性能提升，（n-1）/n

raid5: 至少需要三块硬盘，允许一块盘出错，读写性能提升，（n-1）/n

raid6: 至少需要四块磁盘，允许两块盘出错。读写性能提升，（n-2）/n

raid10：至少需要四块磁盘。允许不同组内个各坏一块盘，读写性能提升，50%

raid01：

jbod：

md，可以组合任何块设备

mdadm，/etc/mdadm.conf

mdadm:模式化的工具

-A  Assemble 装配模式

-C  Create 创建模式

-n #：用于创建RAID设备的个数

-x #: 热备磁盘的个数

-l ：指定RAID级别

-a ：=yes（自动为创建的RAID设备创建设备文件） md mdp part p 如何创建设备文件

-c：指定块的大小，默认为512KB

-F FOLLOW 监控

-S 停止RAID

-D --detail: 显示阵列详细信息

Manage 管理模式专用项

-f：模拟损害

-r：模拟移除设备

-a：模拟添加新设备

watch

-n #:每个#执行一次指定的命令，单位为s

[root@mail ~]# watch -n1 'cat /proc/mdstat'

使用raid0创建一个6G大小的磁盘。

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    [root@mail ~]# fdisk /dev/sdc
    Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
    Building a new DOS disklabel with disk identifier 0xba68f31c.
    Changes will remain in memory only, until you decide to write them.
    After that, of course, the previous content won't be recoverable.
    Warning: invalid flag 0x0000 of partition table 4 will be corrected by w(rite)
    WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
             switch off the mode (command 'c') and change display units to
             sectors (command 'u').
    Command (m for help): n
    Command action
       e   extended
       p   primary partition (1-4)
    p
    Partition number (1-4): 1
    First cylinder (1-2610, default 1):
    Using default value 1
    Last cylinder, +cylinders or +size{K,M,G} (1-2610, default 2610): +6G
    Command (m for help): n
    Command action
       e   extended
       p   primary partition (1-4)
    p
    Partition number (1-4): 2
    First cylinder (785-2610, default 785):
    Using default value 785
    Last cylinder, +cylinders or +size{K,M,G} (785-2610, default 2610): +6G
    Command (m for help): t
    Partition number (1-4): 1
    Hex code (type L to list codes): fd
    Changed system type of partition 1 to fd (Linux raid autodetect)
    Command (m for help): t
    Partition number (1-4): 2
    Hex code (type L to list codes): fd
    Changed system type of partition 2 to fd (Linux raid autodetect)
    Command (m for help): w
    The partition table has been altered!
    Calling ioctl() to re-read partition table.
    Syncing disks.
    [root@mail ~]# mdadm -C /dev/md0 -a yes -l 0 -n 2 /dev/sdc{1,2}
    mdadm: Defaulting to version 1.2 metadata
    mdadm: array /dev/md0 started.
    [root@mail ~]# cat /proc/mdstat
    Personalities : [raid0]
    md0 : active raid0 sdc2[1] sdc1[0]
          12585984 blocks super 1.2 512k chunks
           
    unused devices: <none>
    [root@mail ~]# mdadm -D /dev/md0
    /dev/md0:
            Version : 1.2
      Creation Time : Tue May 10 20:19:43 2016
         Raid Level : raid0
         Array Size : 12585984 (12.00 GiB 12.89 GB)
       Raid Devices : 2
      Total Devices : 2
        Persistence : Superblock is persistent
        Update Time : Tue May 10 20:19:43 2016
              State : clean
     Active Devices : 2
    Working Devices : 2
     Failed Devices : 0
      Spare Devices : 0
         Chunk Size : 512K
               Name : mail.saviorsyang.com:0  (local to host mail.saviorsyang.com)
               UUID : b5ec8803:366d2e9d:a1ddd0f2:58101d5c
             Events : 0
        Number   Major   Minor   RaidDevice State
           0       8       33        0      active sync   /dev/sdc1
           1       8       34        1      active sync   /dev/sdc2
    [root@mail ~]# mke2fs -t ext4 /dev/md0
    mke2fs 1.43-WIP (20-Jun-2013)
    Filesystem label=
    OS type: Linux
    Block size=4096 (log=2)
    Fragment size=4096 (log=2)
    Stride=128 blocks, Stripe width=256 blocks
    786864 inodes, 3146496 blocks
    157324 blocks (5.00%) reserved for the super user
    First data block=0
    Maximum filesystem blocks=3225419776
    97 block groups
    32768 blocks per group, 32768 fragments per group
    8112 inodes per group
    Superblock backups stored on blocks:
      32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208
    Allocating group tables: done                           
    Writing inode tables: done                           
    Creating journal (32768 blocks):
    done
    Writing superblocks and filesystem accounting information: done
    [root@mail ~]# mkdir  /test/md0
    [root@mail ~]# mount /dev/md0 /test/md0
    [root@mail ~]# mount
    /dev/mapper/vg_demo-lv_root on / type ext4 (rw)
    proc on /proc type proc (rw)
    sysfs on /sys type sysfs (rw)
    devpts on /dev/pts type devpts (rw,gid=5,mode=620)
    tmpfs on /dev/shm type tmpfs (rw)
    /dev/sda1 on /boot type ext4 (rw)
    /dev/sdb1 on /student type ext4 (rw)
    /dev/sr0 on /mnt type iso9660 (ro)
    none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
    /dev/md0 on /test/md0 type ext4 (rw)

    使用raid1创建一个2G大小的磁盘。

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    [root@mail ~]# fdisk /dev/sdc
    WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
             switch off the mode (command 'c') and change display units to
             sectors (command 'u').
    Command (m for help): n
    Command action
       e   extended
       p   primary partition (1-4)
    e
    Partition number (1-4):
    Value out of range.
    Partition number (1-4): 3
    First cylinder (1569-2610, default 1569):
    Using default value 1569
    Last cylinder, +cylinders or +size{K,M,G} (1569-2610, default 2610):
    Using default value 2610
    Command (m for help): n
    Command action
       l   logical (5 or over)
       p   primary partition (1-4)
    l
    First cylinder (1569-2610, default 1569):
    Using default value 1569
    Last cylinder, +cylinders or +size{K,M,G} (1569-2610, default 2610): +2G
    Command (m for help): n
    Command action
       l   logical (5 or over)
       p   primary partition (1-4)
    l
    First cylinder (1831-2610, default 1831):
    Using default value 1831
    Last cylinder, +cylinders or +size{K,M,G} (1831-2610, default 2610): +2G
    Command (m for help): w
    The partition table has been altered!
    Calling ioctl() to re-read partition table.
    WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
    The kernel still uses the old table. The new table will be used at
    the next reboot or after you run partprobe(8) or kpartx(8)
    Syncing disks.
    [root@mail ~]# fdisk /dev/sdc
    WARNING: DOS-compatible mode is deprecated. It's strongly recommended to
             switch off the mode (command 'c') and change display units to
             sectors (command 'u').
    Command (m for help): t
    Partition number (1-6): 5
    Hex code (type L to list codes): fd
    Changed system type of partition 5 to fd (Linux raid autodetect)
    Command (m for help): t
    Partition number (1-6): 6
    Hex code (type L to list codes): fd
    Changed system type of partition 6 to fd (Linux raid autodetect)
    Command (m for help): w
    The partition table has been altered!
    Calling ioctl() to re-read partition table.
    WARNING: Re-reading the partition table failed with error 16: Device or resource busy.
    The kernel still uses the old table. The new table will be used at
    the next reboot or after you run partprobe(8) or kpartx(8)
    Syncing disks.
         
    [root@mail ~]# partx /dev/sdc
    # 1:        63- 12594959 ( 12594897 sectors,   6448 MB)
    # 2:  12594960- 25189919 ( 12594960 sectors,   6448 MB)
    # 3:  25189920- 41929649 ( 16739730 sectors,   8570 MB)
    # 4:         0-       -1 (        0 sectors,      0 MB)
    # 5:  25189983- 29398949 (  4208967 sectors,   2154 MB)
    # 6:  29399013- 33607979 (  4208967 sectors,   2154 MB)
    [root@mail ~]# cat /proc/partitions
    major minor  #blocks  name
       8       32   20971520 sdc
       8       33    6297448 sdc1
       8       34    6297480 sdc2
       8       35         31 sdc3
       8       37    2104483 sdc5
       8       38    2104483 sdc6
       8        0   52428800 sda
       8        1     512000 sda1
       8        2   51915776 sda2
       8       16  524288000 sdb
       8       17  524281243 sdb1
       8       48   20971520 sdd
      11        0    3763200 sr0
     252        0   47816704 dm-0
     252        1    4096000 dm-1
       9        0   12585984 md0
    [root@mail ~]# mdadm -C /dev/md1 -a yes -l 1 -n 2 /dev/sdc{5,6}
    mdadm: Note: this array has metadata at the start and
        may not be suitable as a boot device.  If you plan to
        store '/boot' on this device please ensure that
        your boot-loader understands md/v1.x metadata, or use
        --metadata=0.90
    Continue creating array? yes
    mdadm: Defaulting to version 1.2 metadata
    mdadm: array /dev/md1 started.
    [root@mail ~]# cat /proc/mdstat
    Personalities : [raid0] [raid1]
    md1 : active raid1 sdc6[1] sdc5[0]
          2102400 blocks super 1.2 [2/2] [UU]
          [=================>...]  resync = 85.5% (1800064/2102400) finish=0.0min speed=200007K/sec
           
    md0 : active raid0 sdc2[1] sdc1[0]
          12585984 blocks super 1.2 512k chunks
           
    unused devices: <none>
    [root@mail ~]# cat /proc/mdstat
    Personalities : [raid0] [raid1]
    md1 : active raid1 sdc6[1] sdc5[0]
          2102400 blocks super 1.2 [2/2] [UU]
           
    md0 : active raid0 sdc2[1] sdc1[0]
          12585984 blocks super 1.2 512k chunks
           
    unused devices: <none>
    [root@mail ~]#
    [root@mail ~]# mke2fs -t ext4 /dev/md1
    mke2fs 1.43-WIP (20-Jun-2013)
    Filesystem label=
    OS type: Linux
    Block size=4096 (log=2)
    Fragment size=4096 (log=2)
    Stride=0 blocks, Stripe width=0 blocks
    131648 inodes, 525600 blocks
    26280 blocks (5.00%) reserved for the super user
    First data block=0
    Maximum filesystem blocks=541065216
    17 block groups
    32768 blocks per group, 32768 fragments per group
    7744 inodes per group
    Superblock backups stored on blocks:
        32768, 98304, 163840, 229376, 294912
    Allocating group tables: done                           
    Writing inode tables: done                           
    Creating journal (16384 blocks): done
    Writing superblocks and filesystem accounting information: done
    [root@mail ~]# mkdir -pv /test/md1
    [root@mail ~]# mount /dev/md1 /test/md1
    [root@mail ~]# mount
    /dev/mapper/vg_demo-lv_root on / type ext4 (rw)
    proc on /proc type proc (rw)
    sysfs on /sys type sysfs (rw)
    devpts on /dev/pts type devpts (rw,gid=5,mode=620)
    tmpfs on /dev/shm type tmpfs (rw)
    /dev/sda1 on /boot type ext4 (rw)
    /dev/sdb1 on /student type ext4 (rw)
    /dev/sr0 on /mnt type iso9660 (ro)
    none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
    /dev/md1 on /test/md1 type ext4 (rw)

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